Self-adjusting vehicle brake



July 30, 935- R. B. SIMNING SELF-ADJUSTING VEHICLE BRAKE Filed June 19,1933 INVENTOR.

ATTOI'ZNEY.

Patented JulySO, 1935 T OFFICE. '1

, SELF-ADJUSTING VEHICLE BRAKE Roy B. Simning, Minneapolis, Minn.,assignor to San-Esi 00., Minneapolis, Minn., a firm composed of ClementSandberg, Elmer L. Simning E. Nelson, George E. Sandberg, and Roy B.

Application June 19, 1933, Serial No. 676,522

Claims. (c1. res-19.5)

. This invention relates to brake shoe adjustment devices and hasspecial reference to an automatic or self-adjusting mechanism for brakewill appear in the following descriptionthereof.

\ Referring now to the accompanying drawing, iorming part of thisapplication, and wherein like reference characters indicate like'parts:

common hydraulic brake shoe assembly, with. the

- invention attached and the brake applied, portions thereof being shownin sectionfor convenience of illustration.

Figure 2 is a section on the line 22, Figure 1, with the exception thatthe brake'is retracted.

Figure 3 is a section onthe line 3-3, Figurel. It is well known thatsome automobiles are provided with hydraulic service brake mechaa 3 nismcontrolled by a foot pedal having an a pproximate maximum travel ofabout seveninches, of whichonly about three inchesis 'actually employedfor direct application of power to the brake; the other four inchesbeing utilized as in the yieldability of the parts and connections,

together with a suitable margin of safety in respect to action on thepart of the operator. Thus the seven inch stroke will take care of onlyabout one-eighth inch wear on the brake lining without readjustment ofthe brake. However the normal wear of a brake lining is approximatelyone-fourth inch so that if automatic compensation for lining wear isaccomplished without in any way altering the throw of the foot pedal,and this to the entire utilization of the lining as by the instantinvention, the advantages become obvious, for example, in theelimination of expense in connection with frequent brake shoeadjustments. With the instant device the shoes would be adjusted whenthe linings were new and not again require adjustment even when thelinings were worn out, provided the same size linings were used at thetime of renewal. In the embodiment here illustrated, l reprel' sents thebacking plate carrying the brake shoe Other objects and advantages ofthe invention.

Figure 1 is a side elevation of one half of. a

:shoe, and throughja similarly shaped plate It assembly of anautomobile, and 2 the web of a I common hydraulically operated brakeshoe, though it is to be understood that the invention is applicable toanytype of brakeassembly, either manually, hydraulically, orotherwise-operated.

The brake shoe here illustrated isof T-shape in cross section, thehorizontally disposed rim portion beingillustrated at 3, which portioncarries the brake lining 4. In this instance there isillustrateda lining5 fixed to and within the 10 drum 5 of the brake housing. The shoe 2-3is pivotally mounted in the usual manner as at 1, and operated bypressure I of the hydraulic cylinder 8, or other device, at

the opposite end, the retracting spring connec- 15 tion beingillustrated at 9, all of which are common in the art.

Therautomatic adjustment assembly comprises the installationof themember [0 attachedto the backing plate and which attachment is ac- 20'complished by the rivet II at one end and the :pin I! at the oppositeend passing through the web 2 of the shoe. The pin i2 extends through aradially elongated slot 13 in the web 2 of the installed'upon"the'opposite side of the web 2,

though this latter plate ll isjogged or'oflset adjacent its lowermostend, forming an internally inclined shoulder or'bearing l5, spaced fromthe inner edge of the web 2 and from this 30 point contacts the face ofthe member [0, and is held in position by the rivet ll enteringsamethrou'gh 'a"'slightly radially elongated slot It. This connection ismade anti-rattling by the pin it being elongated and extending somecbnsid: erable distance beyond the .plate II where it is circumvented bythe expansive helical spring I1 held in-position by the cap l8, insuringconstant yieldable contact of the plate H against the web 2 of the brakeshoe. Thus there is provided a rectangularlyshaped space l9 intermediateof the innermost edge of the web 2 and the shoulder [5 between theplates It and Ill. It is to be noted that a predetermined elongation ofthehole It is provided in the plate for reception 45 of the rivet II, aswell as an elongation of the hole It in said plate through which the pinI2 passes, and this predetermined elongation of the holes alsodetermines the constant spacing of the lining 4 from the cooperatingface of the brake drum when the brake is in its unapplied position. Thisspace is approximately which is considered ideal for best results, itbeing understood that the plate l4 is-free to move radially just thatpredetermined distance when end of which is-cylindrically formed as at22 and surmounted by an expansive helical spring 23. In the outermostend of this spring is carried the compensating wedge 24, it beingcylindrical in form as at 25 where it is carried in the spring and isflanged as at 26 toprevent dislodgment therefrom, while the remainder ofthe wedge is rectangular in shape and of the exact width of the web 2 ofthe shoe so that it fits readily within the space I9 beneath said weband rides upon the inclined shoulder l5 of the outer plate II. Theoutermost end of this wedge is arcuate in shape so as to bear upwardlyagainst the lower edge of the web of the shoe with the tendency at alltimes to keep the web of the shoe in maximum spaced relation from theshoulder I 5; and the wedge 24 is thus constantly urgedby the spring 23to such service, thus insuring a uniformimovement of the shoe at eachapplication.

The action of the device is'as follows:

Assuming the brake shoe as being provided with. 'a new lining l and inthe engaged position as illustrated in Fig. 1 of the drawing, the wedge24 will remain in its substantially fully-retarded position intermediateof the web 2 of the shoe. and the shoulder l5 of thecompensating'mechanism and in no way interfere with the free movement ofthe brake shoe by the normal operating mechanism therefor except thatthe plate I, which carries the wedge on its shoulder I5, is limited bythe 3 space about the rivet or pin ll; itbeing understood that the shoeis biased constantly toward its fully retracted position by theretracting spring 9 before the wedge 24 was allowed to enter within thespace I9, so that the wedge 24 is constantly taking up anydiiferentiation that exists between the limits of the, shoulder l5 andthe inher edge of the web of the shoe 2, which occurs by reasons of thewear of the'lining, thus, at all times, maintaining a uniform distanceof movement of the shoe. 7

It will of course be understood that the retracting spring is of amplestrength at all times to overcome the urge of the wedge by the spring23, and that the spring I! is sufliciently strong to provide amplefrictional engagement of theplate ll against the shoe web 2 to preventaction of the wedge 24 until the 3 clearance about the rivet II is takenup, and if further movement of the shoe occurs by reason of wear, andovercomes the action of the spring H, as well as spring 8, then thewedge will enter to compensate for such additional movement so that thebrake shoe movement is virtually alwaysthe same.

Having thus described my invention, what I claim and desire to secure byLetters Patent, is:

1. An automatic brake shoe adjuster comprising means having a bearingshoulder thereon radially movably attached to a brake shoe housing,

and wedging means pivotally carried by the brake shoe and extendingbetween said shoulder and 'said brake shoe for the purpose specified.

' against said drum, the combination of means radially movably mountedupon said housing, a

spring biased wedging member pivoted on said shoe and constantly bearingbetween the shoe and said radially movable means to prevent movement ofsaid shoe except within the limits of said radial movement.

4. In a vehicle brake including a bralge drum and housing therefor, anda brake shoe movable against said drum, the combination of radiallymovable means attachable to said shoe and said housing and permitted tomove with said shoe within i'lxed predetermined limits, and a wedgingarm pivoted to said shoe and cooperative with said atedwedging armextendable between said movable means and said shoe to automaticallyadjust said shoe relative to said movable means to compensate for wearof said brake shoe.

ROY B. SIMNING.

movable means to compensate for wear of said

